Introduction to the hottest color distortion pheno

Introduction to color distortion

release date: Source: China packaging

in a broad sense, color distortion refers to the phenomenon that the simulated reproduced color is inconsistent with the color of the object; In the field of printing, color distortion refers to the phenomenon that the printed matter cannot truly reproduce the color of the original, and the color of the printed matter deviates from the color of the original. In the packaging and printing industry, the analysis and correction of image color can make up for the color defects of the original and lay a good foundation for printing. Today, China paper will take you to learn more about the relevant content

1 the main factors leading to color distortion

1) the original has color distortion

printing image originals are mostly obtained by photography. For photo originals, in addition to the color distortion caused by improper operation during shooting, the color is reproduced by color rendering materials such as color pigments, which are prone to color attenuation, which may also cause the distortion of photo color. In addition, with the continuous popularization of digital cameras, there are more and more digital image originals, and the technical requirements of digital cameras for operators are greatly improved. Due to the poor technical level of operators, the captured images are prone to problems such as dim picture and blurred image, resulting in the color distortion of originals

2) color distortion caused by scanning

the image density of the photo original is continuous, and the image information needs to be collected into the computer. When using the scanning equipment to scan the image, it is necessary to divide the image into discontinuous pixels, and collect the R, G and B information of each pixel on the original point by point and line by line. In the process of scanning, it will cause the loss of pixel color information, and image processing is based on the collected image information. All color operations are carried out on this basis, and the color information of the image cannot be added. Therefore, for photo originals, scanning is a very key link in image processing. Improper operation will cause image color distortion

3) color separation processing causes color distortion

printing usually uses C, m, y, K four-color inks to copy colors, while the image information collected by the digital acquisition device is usually R, G, B information. Therefore, before printing and plate making, the image information needs to be converted into C, m, y, K mode, that is, color separation processing. The so-called "color separation" is to decompose and convert the color information of each pixel of the image (generally R, G, B color information) into color information suitable for printing C, m, y, K modes. Color information will be lost in the process of color separation. In color separation, only by correctly setting the color separation parameters (such as set point expansion value, gray balance parameters, black version tone, etc.) according to the printing suitability of ink, paper, etc., can high-quality color separation chips be output and the loss of color information be reduced as much as possible

4) color distortion caused by color restoration

modern printing usually uses C, m, y and K four-color inks to reproduce color. Due to the purity problem of the ink itself, color distortion will also occur during printing overprint

2 how to distinguish color distortion

the main factors leading to color distortion are clear, and how to find color distortion in the actual production process is the key

1) first impression reference method

human eyes have certain adaptability to color. For images with slight color distortion, repeated observation will weaken the recognition ability. Therefore, at this time, the oil inflow increases. When judging whether there is color distortion, it is an important method to use the first eye impression to eliminate the local color vision of human eyes and make the oil pump stop working

2) neutral color benchmark method

there are many neutral colors in life, such as black, white, gray, etc. they are the zero point of color in the colorful world. We can use them as the basis for identifying how to transform, upgrade, innovate and develop polymer materials with color distortion

3) skin color benchmark method

the color that brings confidence to extruder enterprises is the most familiar color. All human images, especially those mainly based on human portraits, can be used as the basis to distinguish color distortion according to the color of skin. Whether yellow skin, white skin or black skin, there is a rule in their skin color, that is, they are all blood color. That is, there is red in yellow, red in white or red in black. If the color of the person in the image is yellow, it will give people a sick feeling. Under normal circumstances, even if the skin color of the person in the image is really yellow, it should also be adjusted to blood color during color correction, that is, there is red in yellow

4) key color reference method

key colors are memory colors, such as blue in the sky, green in the grass, etc. Memory color is the most common color in life. As prepress staff, we should strengthen the training of color memory, observe more carefully at ordinary times, constantly carry out visual training and accumulate experience, and use our own memory to restore the original color of the image in color correction

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